Hot strip rolling



Feb. l5, 1938. R. l.. LEFFLER 2,108,379

HOT STRIP ROLLING w Filed May v19, 1936 2 sheets-sheet 1 ,415T P455 /A/ v HOLL/N6 B/LLET @lign/Z021' 'E055 L .y LEFFLE/e,

Feb. 15, 19385. R51.; lLEM-'LER A HOT STRIP ROLLING I FiledMay 19, 195e z sheetssheet 2 @dan 'E55 L LEF/FL 5E,

Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE HOT STRIP ROLLING Ross Leiler, McKeesport, Pa. ApplicationMay 19, 1936, Serial No. 80,594

3 Claims.

4'I'hisinvention relates to the rolling of metal, and is particularly concerned with the hot rolling of steel, one of the objects being to roll sections or shapes, particularly rectangular shapes, of greater width than thickness in such a manner that a greater portion of the surface of the metal is worked than.-was heretofore possible. A more specific object is to hot-roll steel strip so that its entire surface receives at least some working. The term strip-as here used is intended to cover products such as sheet bar, skelp, etc. Other objects may be inferred from the fol lowing disclosure.

As an example of the invention, a steel bloom is heated to a proper rolling temperature and worked into a square billet by any conventional method that will produce oppositely rolled corners. Ordinarily, this necessitates diagonal rolling, the oval square, diamond square and diamond methods being examples. Then, on the same heat, this billet is rolled on its opposite diagonal to atten it into strip by spreading so that its previously rolled corners become the edges of this strip. To do this, the corners of the billet between its previously'rolled corners are rolled in such a manner as to permit lateral spreading of its previously rolled corners.

The described procedureresults in the entire surface of the strip being worked. It is to be understood that the volume of the vmetal is proportioned along with the various reductions t0 provide a strip of the width and thickness desired.

Referring to the accompanying drawings: Figure 1 shows the last pass in the reduction of the bloom to the billet.

Figure 2 shows the pass beginning the reduction of this billet to the desired strip.

Figures 3 through 6 show the successive passes required to produce the strip.

Figure 1 represents the final pass 4usedl in reducing the bloom to the billet. The corners rolled onto the billet by this pass are numeraled I, and the corners that cannot beso rolled are 45 numeraled 2. This figure is included only to emphasize the fact that the rolling .of the billet must be done in such a manner as toprovide' opposite rolled corners.

This billet is now entered on its opposite diagonal into pass #1 -shown by Figure 2, the billet being here illustrated by the broken lines and vthe outline of the pass by the solid lines. It will be` noted that the diagonal between the corners Iis now horizontal, While that between the corners- 2 is `vertical. The pass itself is formed by rolls having grooves providing 'diagonal square or diamond surfaces 3 which work a majority of the surface'of the billet and iiat surfaces 4 that are oppositely spaced to provide recesses into which the previously rolled corners I may 5 spread. This'flrst pass is open since edge control is not necessary at this time.

Pass #2 vshown by Figure 3 differs somewhat in that it isa closed one to provide some edge control and its diagonal square or diamond is of reduced area. -Otherwise, surfaces Ila and 4a are for the same purposes -as the surfaces' 3 and 4 in the case of the pass #1.

Pass #3 shown by Figure 4 is a closed flat pass which completely attens the billet and provides for the edge control required to assure strip of the proper Width. This pass and passes #4 and #5 illustrated by Figures 5 and 6 may be considered as conventional iiat passes, and in them the strip is further formed and finished.

The showing of the work by broken lines and the pass by solid lines, as explained in connection with pass #1, is maintained throughout these other figures. It is to be observed that the corners I of the billet eventually become the edges of the strip, the corners 2 disappearing at pass #3 to become the flattened section of thestrip. The work does not require turning. In passes #l and #2 the surfaces- 3 and 3a provide thickened central sections of metal which eventually flows laterally and longitudinally into width and length, this eliminating the lateral stretching- -usually required to provide the strip with its proper Width. -The manner in which the width and thickness of the strip can be controlled or varied is obvious.

An important advantage connected with what has been disclosed consists in the fact that the edges of the strip are actually the corners I rolled into the billet by the last pass used in its formation and which is illustrated by Figure 1. It is obvious that these edges ewill be superior to those produced by the methods hel Jofore in vogue.

.Another great advantage is that it is possible to construct passes #1 and #2 so that a great majority of the surface of the steel is worked while it is still in a plastic state. Although not previously mentioned, it is to be understood that in the interests of economy the rolling must be done on a single 'heat from the bloom through the billet and down to the final strip, and that due to rapid cooling the steel may not be in a plastic state after it reaches pass #4. In the -usual lmethods of rolling strip the work is kept three passes only a relatively small proportion of its surface is actually worked. By rolling the ingot on its diagonal in the manner described it is possible to use a pass like that shown by Figure 2 wherein diagonal square or diamond grooves of relatively great depth are provided tov work a great majority of the metals surface, the only portions unworked being those which spread into the recesses .4 and which have already been worked by the previous rolling ci the square billet on its opposite diagonal. The same advantages are involved by pass #2, while pass #3 works the metal sufficiently thin to accomplish the same thing to a considerable extent.

The term plastic state as used above is not intended to mean that the steel is not suiilciently malleable to be rolled in passes #4, #5 and #6, but means that the steel falls to a temperature in or below its critical range about the time it reaches pass #4.

dieser@ l claim: Y

l. A hot strip rolling method including producing a billet with rolled opposite corners and rolling down parts of said billet between said corners while permitting the latter to spread and become edges of the strip.

2. A hot strip rolling method including producing a rectangular billet by diagonal rolling and rolling said billet on its opposite diagonal to iiatten it into strip and to spread its previously rolled corners so they become the edges of said strip.

3. A hot strip rolling method including producing a rectangular billet by diagonal rolling, rolling against a majority of the surface of said billet on its opposite diagonal while permitting its corners to spread laterally, attening into strip by rolling on its same diagonal and forming said corners into the edges of said strip.

Ross i.. 

